DTC Troubleshooting: P1129
DTC P1129: MAP Sensor Signal Higher Than Expected
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P1129 MAP Sensor Signal Higher Than Expected
      

1.
Vacuum leak check:

Vacuum leak check
?1.
Check for vacuum leaks in these parts:
PCV valve
PCV hose
EVAP canister purge valve
Throttle body
Intake manifold
Brake booster
Brake booster hose

Are there any vacuum leaks?

     
YES
     
     
     
Repair or replace the parts with vacuum leaks.?
     
NO
     
     
     
Go to step 2.
2.
MAP sensor performance check:

MAP sensor performance check
?1.
Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.

?2.
Check the parameter(s) below with the HDS for 5 seconds.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
MAP SENSOR
More than 36.9
kPa
    

Do the current conditions meet the threshold for 5 seconds or more?

     
YES
     
     
     
     
NO
     
     
     
Go to step 3.
3.
Problem verification:

Problem verification
?1.
Clear the DTC with the HDS.


?2.
Test-drive under these conditions:
Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
Engine speed between 1,400?6,700 rpm
Transmission in D
Drive at a steady speed between 55?75 mph (90?120 km/h) for 10 seconds, then decelerate (with the throttle fully closed) for 2 seconds

Signal
Current conditions
Values
Unit
ECT SENSOR 1
    
ENGINE SPEED
    
VEHICLE SPEED
    

?3.
Monitor the OBD STATUS for DTC P1129 in the DTCs MENU with the HDS.
DTC Description
OBD STATUS
P1129 MAP Sensor Signal Higher Than Expected
  

Does the HDS indicate FAILED?

     
YES
     
     
     
The failure is duplicated. Replace the MAP sensor.?
     
NO
     
     
     
If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the MAP sensor and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot. If the HDS indicates NOT COMPLETED, go to step 3-2 and recheck.?